Field of the Invention
The present application relates generally to switched electrical devices. More particularly, the present application is directed to circuit interrupting devices, such as ground fault circuit interrupter (GFCI) devices, that switch to a “tripped” or unlatched state from a “reset” or latched state when one or more conditions is detected. Such devices consistent with the invention disclosed have a more compact latching mechanism than conventional devices and provide a reusable feature that electronically prevents a miswire condition.
Description of Related Art
Switched electrical devices having contacts that are biased toward the open position require a latching mechanism for setting and holding the contacts in a closed position. Likewise, switched electrical devices having contacts that are biased toward the closed position require a latching mechanism for setting and holding the contacts in an open position. Examples of conventional types of devices include devices of the circuit interrupting type, such as circuit breakers, arc fault interrupters and ground fault circuit interrupters (GFCI), to name a few. Electrical receptacles having built-in ground fault protection circuitry, i.e., GFCI receptacles, are ubiquitous. Such protection circuitry and the associated mechanisms normally take up a substantial amount of the physical space within a receptacle housing, the size of which is limited by the standard junction boxes in which they must fit. The trend toward including additional safety and other features, many required by evolving industry standards, has made it necessary to economize on interior receptacle space wherever possible.
GFCI receptacles typically use a mechanical latch for holding the contacts closed, and a solenoid, a relay, or some other such actuating device, for tripping the latch to open the contacts when an actual fault is detected or when the mechanism of the device for detecting such faults is tested. Typical mechanisms for tripping and resetting the contacts employ an arrangement in which the axis of the trip solenoid and the motion of a linked latch plate are perpendicular to the axis of a reset button and/or plunger. Despite the trend toward miniaturization, such arrangements tend to be wasteful of available space.
Additional industry standards for such circuit interrupting devices, either presently accepted or contemplated for the future, include: denying power to the user accessible and/or downstream load terminals of the device when AC power is improperly applied to the load side terminals of the device, known as a miswire condition; testing for proper operation of the device after subjecting the device to a sudden force, known as the shock, or drop, test; and providing a mechanism by which proper operation of the device is periodically confirmed without the need for human intervention, known as self-test. Conventional devices that may or may not address one or more of these additional industry requirements tend to be too large, ineffective, and/or do not provide a robust method for confirming proper functioning of the device.